Delete a key from a MongoDB document using Mongoose

Question

I\'m using the Mongoose Library for accessing MongoDB with node.js

Is there a way to remove a key from a document? i.e. not just set the value to n

Answer 1

I use mongoose and using any of the above functions did me the requirement. The function compiles error free but the field would still remain.

user.set('key_to_delete', undefined, {strict: false} );

did the trick for me.

Answer 2

the problem with all of these answers is that they work for one field. for example let's say i want delete all fields from my Document if they were an empty string "". First you should check if field is empty string put it to $unset :

function unsetEmptyFields(updateData) {
  const $unset = {};
  Object.keys(updatedData).forEach((key) => {
    if (!updatedData[key]) {
      $unset[key] = 1;
      delete updatedData[key];
    }
  });
  updatedData.$unset = $unset;

  if (isEmpty(updatedData.$unset)) { delete updatedData.$unset; }

  return updatedData;
}

function updateUserModel(data){
const updatedData = UnsetEmptyFiled(data);

    const Id = "";
    User.findOneAndUpdate(
      { _id: Id },
      updatedData, { new: true },
    );
}

Answer 3

In early versions, you would have needed to drop down the node-mongodb-native driver. Each model has a collection object that contains all the methods that node-mongodb-native offers. So you can do the action in question by this:

User.collection.update({_id: user._id}, {$unset: {field: 1 }});

Since version 2.0 you can do:

User.update({_id: user._id}, {$unset: {field: 1 }}, callback);

And since version 2.4, if you have an instance of a model already you can do:

doc.field = undefined;
doc.save(callback);

Answer 4

I'm trying to remove a field called 'cover' from my document but it is of type buffer. so for some reason even if I make it undefined it still remains binary type while giving me undefined result this route returns the cover field from document matching profile property

`

exports.update = (req, res) => {
  let form = new formidable.IncomingForm();
  form.keepExtension = true;
  form.parse(req, (err, fields, files) => {
    if (err) {
      return res.status(400).json({
        error: "Photo could not be uploaded",
      });
    }
    let user = req.profile;
    user = _.extend(user, fields);

    if (fields.password && fields.password.length < 6) {
      return res.status(400).json({
        error: "Password should be min 6 characters long",
      });
    }
    if (fields.cover == null) {
      user.cover = undefined;
    }

    if (files.photo) {
      if (files.photo.size > 10000000) {
        return res.status(400).json({
          error: "Image should be less than 1mb",
        });
      }
      sharp(files.photo.path)
        .resize(300, 300, {
          fit: "cover",
        })
        .jpeg({
          quality: 90,
        })
        .toFile(`assets/users/${user.profile}.jpg`, (err, info) => {
          if (err) {
            return res.status(400).json({
              error: "unable to process the image",
            });
          }
        });
    }
    if (files.cover) {
      if (files.cover.size > 10000000) {
        return res.status(400).json({
          error: "Image should be less than 1mb",
        });
      }
      sharp(files.cover.path)
        .resize(1200, 675, {
          fit: "cover",
        })
        .jpeg({
          quality: 90,
        })
        .toBuffer((err, compressed, info) => {
          User.findOneAndUpdate(
            { profile: user.profile },
            { cover: compressed }
          )
            .select("_id")
            .exec((err, updatedUser) => {
              if (err)
                res.status(400).json({
                  error: "Unable to process the image",
                });
            });
        });
    }

    console.log("user", user);

    user.save((err, result) => {
      if (err) {
        return res.status(400).json({
          error: errorHandler(err),
        });
      }
      user.hashed_password = undefined;
      user.salt = undefined;
      user.photo = undefined;
      res.json(user);
      console.log("result", result);
    });
  });
};

`

Answer 5

you can use delete user._doc.key